LegalOne Entreprises

Français

A free, read-only REST API and a keyless MCP server for public data on French companies, plus helper tools for French legal notices (annonces légales).

• Companies: identity, head office, establishments, share capital, current officers (name and role), from INSEE Sirene and INPI RNE.

• BODACC notices: latest notices of a company (creation, changes, sale of a business, insolvency proceedings, removal) and deeds and accounts filings listed at the INPI.

• Addresses: autocomplete, normalisation and reverse geocoding with the Base Adresse Nationale.

• Legal notices: which notices a corporate event requires, their legal basis and regulated rate, next steps, and a draft that the user reviews and publishes on legalone.fr.

The MCP server is listed as LegalOne Entreprises (a different, unrelated product is named "LegalOne" in the MCP registry).

This repository holds the public client material only: an agent skill, two single-file SDKs (TypeScript, Python) and the MCP registry manifest.

MCP server

Tools: search_companies, get_company, get_establishment, list_bodacc_notices, get_bodacc_notice, list_company_documents, search_addresses, get_legal_notice_price, which_legal_notice, get_next_steps, prepare_legal_notice. All are read-only except prepare_legal_notice, which saves a draft on legalone.fr. Nothing is paid in the chat.

Claude (claude.ai and Claude Desktop): Settings > Connectors > Add custom connector, name LegalOne Entreprises, URL https://mcp.legalone.fr/mcp, no authentication. Connectors added on claude.ai are also available in Claude Desktop.

Claude Code:

claude mcp add --transport http legalone-entreprises https://mcp.legalone.fr/mcp

ChatGPT: Settings > Apps & Connectors > Advanced settings, turn on developer mode, then create a connector with the URL https://mcp.legalone.fr/mcp and no authentication. Availability depends on your ChatGPT plan; menu names may change.

Other clients that accept a remote server:

{
  "mcpServers": {
    "legalone-entreprises": { "url": "https://mcp.legalone.fr/mcp" }
  }
}

Clients that only speak stdio can go through a bridge such as npx -y mcp-remote https://mcp.legalone.fr/mcp.

Related MCP server: mcp-insee-entreprises

REST API

Keep the key server-side; never ship it in client code.

# Company profile by SIREN
curl -s https://api.legalone.fr/v1/entreprises/552032534 \
  -H "Authorization: Bearer $LEGALONE_API_KEY"

# Search by start of name, or exact SIREN/SIRET
curl -s --get https://api.legalone.fr/v1/entreprises \
  --data-urlencode "q=exemple" -H "Authorization: Bearer $LEGALONE_API_KEY"

# Latest BODACC notices
curl -s "https://api.legalone.fr/v1/entreprises/552032534/bodacc?limit=5" \
  -H "Authorization: Bearer $LEGALONE_API_KEY"

# Normalise an address
curl -s --get https://api.legalone.fr/v1/adresses/normaliser \
  --data-urlencode "q=8 boulevard du Port 80000 Amiens" \
  -H "Authorization: Bearer $LEGALONE_API_KEY"

Every response is { data, meta, links }; meta carries updatedAt, sources, warnings and attribution. Errors use RFC 9457 (application/problem+json): 400 bad parameter, 401 missing or invalid key, 404 unknown or not publicly available (treat as "not found", do not retry), 429 quota exceeded (wait for Retry-After), 503 retry later. The full list of routes is in the OpenAPI contract and in SKILL.md.

SDKs

Each SDK is one file with no dependency: copy it into your project.

// sdk/typescript/legalone.ts — native fetch (Node 18+, browsers, Deno, Bun)
import { LegalOne } from "./legalone.ts";

const api = new LegalOne({ apiKey: process.env.LEGALONE_API_KEY! });
const company = await api.getCompany("552032534"); // null if not found
console.log(company?.data.name, company?.meta.attribution);

# sdk/python/legalone.py — standard library only, Python 3.9+
from legalone import LegalOne

api = LegalOne(api_key="lo_...")
company = api.get_company("552032534")  # None if not found
if company:
    print(company["data"]["name"], company["meta"]["attribution"])

Methods: getCompany / get_company, getEstablishment, searchCompanies, listBodaccNotices, getBodaccNotice, listCompanyDocuments, health. Errors raise LegalOneError (status, title, detail, request id, retry delay on 429). Code comments and error messages are in French.

Python tests (local loopback server, no network): cd sdk/python && python3 -m unittest -v.

Agent skill

SKILL.md tells an agent when and how to use the API or the MCP server. Claude Code: copy it to .claude/skills/legalone/SKILL.md. Other agents: point them to https://api.legalone.fr/skill.md.

Data sources and licences

Each response lists the sources actually used, with their update date, in meta.sources.

Attribution (required)

Display meta.attribution next to the data, as is. For company data it reads:

Données : LegalOne — sources INSEE Sirene, INPI RNE, DILA BODACC, mise à jour le {date}

{date} is meta.updatedAt as DD/MM/YYYY; "LegalOne" links to the company page (data.links.legalone) or to https://legalone.fr. Address routes read Adresses : Base Adresse Nationale (BAN), Licence Ouverte 2.0 — via LegalOne. Do not present the data as certified by INPI or INSEE.

Limits

• The data is for pre-filling and enrichment. It is not a regulatory identity (KYC) source and not legal proof: verify on an official Kbis or RNE extract.

• Personal data is limited to an officer's name and role. No contact details, no people search, no financial statements, no beneficial owners.

• Companies whose data is not publicly distributed, and companies or people who objected to publication on LegalOne, are not served.

• Legal-notice rules and steps are indicative; ask a legal professional when a situation is unusual.

Terms, privacy, support

• Terms of use: https://legalone.fr/developers/conditions

• Privacy: https://legalone.fr/developers/conditions#confidentialite

• Objection (GDPR) or correction request: https://legalone.fr/developers/opposition

• Support: api@legalone.fr

Licence

The code and documentation in this repository are under the MIT licence. Data returned by the API remains under the source licences above and the LegalOne terms of use.